New poll shows Democrats' lead expanding ahead of midterms

52% of registered voters would like to see the Democrats control Congress after the November elections, while 40% prefer Republicans, according to a new NBC News/Wall Street Journal poll.

Why it matters: This is the biggest lead Democrats have held yet in midterm polling from NBC/WSJ, and it's bolstered by figures that show more Democrats turned out in House primaries than Republicans for the first time since 2008. The poll also indicates, however, that Republican enthusiasm for the midterms has increased.